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Creative Biostructure provides a full range of products and services based on our unparalleled Mempro™ Liposome platform. Our featured Mempro™ Liposome Preparation services involve a variety of mechanical and non-mechanical methods, among which reverse phase evaporation technique is a generally employed one.
The reverse phase evaporation technique is composed of inverted micelles or water-in-oil emulsions in which the water phase contains the interested drugs and the organic phase consists of the lipids to form liposomal bilayer. More... (In brief, we add this lipid mixture to a flask and evaporate the solvents to obtain lipid films. Then, an organic phase mostly composed of isopropyl ether and/or diethyl ether is used to dissolve the lipid films again. Addition of the water phase leads to a two-phase system, and the subsequent sonication results in a homogeneous dispersion. The organic solvent was slowly evaporated, and the system transformed into a viscous gel as a result, which forms a liposome-containing aqueous suspension. Compared to the thin-film hydration method, the reverse phase evaporation technique shows an advantage of higher internal aqueous loading. Methods such as dialysis and centrifugation can be applied to remove the remaining solvent, whereas a small amount of organic solvent may not be removed, which is able to further interact with the lipids or the drugs.)
Figure 1. Flow Chart of Reverse Phase Evaporation
The CO2 can be acted as a convenient solvent at supercritical conditions since it is dense and non-condensable. Therefore, supercritical CO2 (scCO2) was introduced into the novel supercritical reverse phase evaporation method to dissolve the lipids. More...(As shown in Figure 2, a high pressure pump propels gaseous CO2 into a variable volume view cell with a magnetic stir bar, and the inside temperature and pressure are increased to a proper supercritical value. By using the HPLC pump, aqueous drug-containing solution can be slowly introduced into the cell to reach the desired concentration. Then, the pressure is reduced to release the CO2, resulting in formation of a liposomal dispersion with improved entrapment efficiency.)
Figure 2. Schemed diagram of novel supercritical reverse phase evaporation (SRPE). Supercritical CO2 (scCO2) was introduced into the SRPE method to dissolve the phospholipids. (B. S. Pattni, et al., 2015)
Advantages of SPRE：
Besides reverse phase evaporation method, Creative Biostructure provides a full package of liposome preparation services based on our cutting-edge Mempro™ Liposome Technology. We have a group of rich-experienced scientific elites to ensure the best products and services for your custom demands. Creative Biostructure aims to be your reliable research partner. Please feel free to contact us for a detailed quote.
G. Corace, et al. (2014). Multifunctional liposomes for nasal delivery of the anti-Alzheimer drug tacrine hydrochloride. Journal of Liposome Research, 24(4): 323-335.
B. S. Pattni, et al. (2015). New Developments in Liposomal Drug Delivery. Chemical Reviews, 115 (19): pp 10938–10966.
R. S. Kalhapure, et al. (2015). Nanoengineered Drug Delivery Systems for Enhancing Antibiotic Therapy. Journal of Pharmaceutical Sciences, 104(3): 872-905.